I really don't know how anyone can _____ your constant complaint; no wonder you have lost so many friends.

A．come up with

B．end up with

C．put up with

D．keep up with

铅烟的时间加权平均容许浓度是0.03mg／m³，某工厂浓度为0.12mg／m³时，在监督管理中，其危害为几级（）。

A.Ⅰ级

B.Ⅱ级

C.Ⅳ级

D.Ⅴ级

E.Ⅵ级